Batches of partially spray-dried lactose tablets with three different initial tensile strength (similar to 20 N, similar to 35 N, similar to 50 N) were made. Changes along a 24 h long thermal treatment at 100 degrees C in tensile strength, friability, individual mass, water content, disintegration time, average free volume and wetting properties were evaluated. Caffeine containing gastroresistant pellets were gained by drug layering and filmcoating of inert microcrystalline cellulose pellet cores in fluid bed equipment. Shape, size, mechanical properties, drug content and dissolution profile of the coated pellets were determined. Batches of pellet containing tablets with three different pellet-filler ratios were compressed where partially spray-dried lactose was used as a filler-binder material. Characteristics of pellet containing tablets were evaluated before and after a 24 h long thermal treatment at 100 degrees C. Results shown that the poor initial mechanical properties (friability, tensile strength) were improved by thermal exposure while there were no remarkable alterations in drug release profiles. (C) 2015 Elsevier B.V. All rights reserved.